Tabloid celebrity magazine The National Enquirer claims that the 18-year-old is currently attending college dressed as a man and calls herself Stephen.

Beatty, 73, and Bening, 52, are said to be everything from 'supportive' to 'devastated' by their eldest daughter's decision.

"Warren Beatty is beside himself over the situation with his daughter Kathlyn," a source told the National Enquirer. "He and Annette have tried to deal with this over the years when their daughter was younger, but she's determined to go ahead with the transgender operation. She repeatedly told her parents that once she turns 18 she would take matters into her own hands."

Beatty and Bening, who met on the set of 'Bugsy,' married in 1992 and have four children together, Kathlyn, 18, Benjamin, 16, Isabel, 13 and Ella, 10.